1. Technical Field of the Invention
The present invention relates to a technology for discriminating between a sound uttered by a human being (hereinafter referred to as a “vocal sound”) and a sound other than the vocal sound (hereinafter referred to as a “non-vocal sound”).
2. Description of the Related Art
A technology for discriminating between a vocal sound interval and a non-vocal sound interval in a sound such as a sound received by a sound receiving device (hereinafter referred to as an “input sound”) has been suggested. For example, Japanese Patent Application Publication No. 2000-132177 describes a technology for determining presence or absence of a vocal sound based on the magnitude of frequency components belonging to a predetermined range of frequencies of the input sound.
However, noise has a variety of frequency characteristics and may occur within a range of frequencies used to determine presence or absence of a vocal sound. Thus, it is difficult to determine presence or absence of a vocal sound with sufficiently high accuracy based on the technology of Japanese Patent Application Publication No. 2000-132177.